@Maddog77:
Why yes it is! My son acquired that from some Army friends of ours. It’s a showpiece and, obviously, not a live round. Good eye for the detail too.
It caught my attention because I own an empty .50cal heavy machine gun round which I bought at an antique show. From the different shape and apparently larger size of the round on your shelf, I took a guess that it was the 20mm type. I think that bits of military paraphernalia like this (things like flags, propaganda posters, maps, officer caps, 1940s-style rotary telephones, medals and so forth) make wonderful “set decorations” in a war-themed gaming room and really help to create an inspiring atmosphere.